L, layer structure

Au39(PPh3)uCl6]Cl2 has al 9 9 l 9 9 l layered structure in which the central gold is surrounded by other golds [187]. 

Millini R, Perego G, Parker Jr WO, Bellussi G, Carluccio L. Layered structure of ERB-1 microporous borosilicate precursor and its intercalation properties towards polar molecules. Micropor Mater 1995 4 221-30. 

Layered Structures. Whenever a barrier polymer lacks the necessary mechanical properties for an appHcation or the barrier would be adequate with only a small amount of the more expensive barrier polymer, a multilayer stmcture via coextmsion or lamination is appropriate. Whenever the barrier polymer is difficult to melt process or a particular traditional substrate such as paper or cellophane [9005-81-6] is necessary, a coating either from latex or a solvent is appropriate. A layered stmcture uses the barrier polymer most efficiently since permeation must occur through the barrier polymer and not around the barrier polymer. No short cuts are allowed for a permeant. The barrier properties of these stmctures are described by the permeance which is described in equation 16 where and L are the permeabiUties and thicknesses of the layers. 

L. Blum. Structure of the electric double layer. In I. Prigogine, S. A. Rice, eds. Advances in Chemical Physics, Vol. 78, New York Wiley, 1990, pp. 171-222. L. Blum. The electric double layer—a comprehensive approach. In C. A. Croxton, ed. Fluid Interfacial Phenomena. New York Wiley, 1986, pp. 391-436. 

Figure 9.11 Alternative representations of the layer structures of (a) kaolinite, (b) pyrophyllite, and (c) talc. (After H. J. Emeleus and J. S. Anderson, 1960 and B. Mason and L. G. Berry, 1968.)...

The electrical double-layer structure at Au(l 11), Au(110), Au(100), and Au(210) faces and at a pc-Au electrode has been studied in 5 x 10 3 and 1 x 10-2 M LiC104 solutions in DMSO by cyclic voltammetry and impedance methods.477 The electrodes were cleaned by heating in a flame ... 

For the still-unsolved, hexagonal structure type of GdSI, only the cell dimensions are presented. The structures were described in detail by Dagron and Thevet (.96). Their common building-principle is a layer structure formed by planar layers [LS] (L = metal), separated by a double layer of bromine or iodine. The plane layers [LS] eu e formed by the juxtaposition of metal tetrahedra enclosing sulfur, [L4S]. These layers exhibit two different synunetries. 

Zareba et al. [165] described the crystal structure of the chiral 4-(l-methyl-heptyloxycarbonyl)-phenyl 4-heptyloxytolane-4 -carboxylate (C7-tolane) which shows monotropic antiferroelectric and ferroelectric phases. The single-crystal X-ray analysis of this compound shows that the crystal has a smectic-like layer structure composed of largely bent molecules where the chain of the chiral group is almost perpendicular (86°) to the core moiety. Within the layers, the molecules are tilted. The central tolane group of the molecule is roughly planar. 

Conjugated polymers doped with C60 become p-type semiconductors [305,306] some LB films of two polyalkylthiophenes mixed with arachidic acid and doped with C60 have been prepared [307]. The films of polyalkylthiophene + arachidic acid -l- C60 (spread from mixtures of 1.0 0.33 0.1 ratio) on ITO glass had a well-defined layer structure, as confirmed by x-ray diffraction. The bilayer distance obtained from the Bragg equation was 5.6 nm, the same as for arachidic acid LB films. Since the films were spread on subphases containing... 

Molybdenum trioxide has a layered structure with orthorhombic symetry [16] (a=3.963, b=ll855, c=3.696 A), this structure consists of double layer sheets parallel to the (010) cleavage plane. The building unit is a distorted M0O6 octahedron, with Mo-0 distances 1.67, 1.73, 1.95 (twice), 2.25 and 2.33 A (Fig.l)... 

For nearly symmetric compositions the unlike blocks form domains composed of alternating layers, known as lamellar phase (L). Slightly off-symmetry composition results in the formation of a different layered structure. The structure is known as perforated layers (PI) or catenoid phase. Despite an earlier assignment as an equilibrium phase, it is now known to be in a long-lived metastable state that facilitates the transition from I to G phases [9-14], The PL structure consists of alternating minority and majority component layers in which hexagonally packed channels of the majority component extend through the minority component. 

Kato, K. Zheng, C. Dey, S. K. Torii, Y. 1997. Chemistry of the alkoxy-derived precursor solutions for layer-structured perovskite thin films. Int. Ferro. 18(l-4) 225-235. 

An example of a layer structure mixed conductor is provided by the cathode material L CoC used in lithium batteries. In this solid the ionic conductivity component is due to the migration of Li+ ions between sheets of electronically conducting C0O2. The production of a successful mixed conductor by doping can be illustrated by the oxide Cei-jPxx02- Reduction of this solid produces oxygen vacancies and Pr3+ ions. The electronic conductivity mechanism in these oxides is believed to be by way of electron hopping between Pr4+ and Pr3+, and the ionic conductivity is essentially vacancy diffusion of O2- ions. 

Figure 25. Plots of the log(lo/l -1) against the distance between the donor and the acceptor layers. Structure of the composite LB films with the donor - spacer - acceptor layers in the insert.

A. Bolognesi, C. Botta, and L. Cecchinato, Optical properties and electroluminescence of poly(3-alkylmethoxy-thiophene) single- and double-layer structures, Synth. Met., 111-112 187-189, 2000. 

G.L. Frey, K.J. Reynolds, R.H. Friend, H. Cohen, and Y. Feldman, Solution-processed anodes from layer-structure materials for high efficiency polymer light-emitting diodes, Am. Chem. Soc., 125 5998-6007, 2003. 

Kamarajugadda, S., and Mazumder, S. Numerical investigation of the effect of cathode catalyst layer structure and composition on polymer electrolyte membrane fuel cell performance. Journal of Power Sources 2008 183 629-642. Krishnan, L., Morris, E. A., and Eisman, G. A. Pt black polymer electrolyte-based membrane-based electrode revisited. Journal of the Electrochemical Society 2008 155 B869-B876. 

We shall consider only multilayers of finite transverse extent. Such structures are formed by L layers of finite thicknesses, with refractive indexes Ui, I = l,2,...,L. The coordinates of the interfaces between adjacent layers are denoted by Xi, I = l,2,...,L — I, and Xq and x are the outer coordinates of the structure. We will suppose for a while that the multilayer is enclosed between a pair of perfect electric or magnetic conductors (electric or magnetic walls ). More complex boundary conditions will be briefly discussed later. 

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